“We have no reason to believe that Baghdadi's not still alive, but we have not heard from him since the end of last year,” Brett McGurk told reporters at the White House, noting that Baghdadi may use the Muslim holy month of Ramadan to message his "so-called followers".

“We have not heard from him,” he said, “But we presume that he's still alive.”

McGurk made the comments while updating reporters on the anti-Daesh campaign.

He said the group’s “morale is plummeting, they're executing their own fighters” as Daesh continues to be squeezed by Iraqi and Kurdish forces in Iraq, and fighters in Syria.

“They have not had a successful offensive operation, particularly in Iraq, in over a year,” McGurk said. “They've lost about 50 percent of their territory, about 20 percent of their territory in Syria, and it's continuing to shrink."

Their forces have been reduced to the “lowest historic point” since the anti-Daesh offensive began, hovering between 19,000 and 25,000 fighters, he said.

That’s down from original force estimates that put the number of Daesh fighters at around 31,000.

In addition, mid and senior level officials have been killed at a rate of one every three days, McGurk added.

“We've taken out about 100 just over the last few months alone, and this is because of the intelligence that we're able to gather from everything that we're doing,” he said.

The terror group has not only halved its salaries to its fighters as it progressively finds itself on the back foot in Syria and Iraq, but has also reportedly started executing fighters suspected of passing along vital information to anti-Daesh forces, including the U.S.-led coalition.

U.S.-backed forces in Syria are attempting to cut the final major hub linking Daesh's self-proclaimed capital, Raqqa, with the Turkish border.

The city's liberation could yield valuable information about Daesh's leadership networks that "will be very important for further unraveling" the group, McGurk said.